improve doc comments

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

syft/pkg/language.go

@@ -1,8 +1,10 @@
 package pkg
 
+// Language represents a single programming language.
 type Language string
 
 const (
+	// the full set of supported programming languages
 	UnknownLanguage Language = "UnknownLanguage"
 	Java            Language = "java"
 	JavaScript      Language = "javascript"
@@ -11,6 +13,7 @@ const (
 	Go              Language = "go"
 )
 
+// AllLanguages is a set of all programming languages detected by syft.
 var AllLanguages = []Language{
 	Java,
 	JavaScript,
@@ -19,6 +22,7 @@ var AllLanguages = []Language{
 	Go,
 }
 
+// String returns the string representation of the language.
 func (l Language) String() string {
 	return string(l)
 }